What You’ll Need
- Glass of water
- 4 teaspoons table salt
- Glass bowl
- Magnifying glass
What You'll Do
- Dissolve the salt in the glass of water.
- Pour some of the salt water into a shallow glass bowl.
- Put the bowl in a warm place so that the water evaporates quickly.
- Once all the water is gone, use a magnifying glass to look at the crystals.
How It Works
Table salt is a mineral called sodium chloride. (Minerals are substances that are formed naturally in the ground.) As the solvent (in this case, water) evaporates, the molecules of this mineral draw together into flat surfaces at right angles. That’s why each crystal looks square or rectangular, like a cube.
Extend the Fun
Younger kids: Play with the color of the crystals by adding food coloring. Help your child pour the water and salt mixture into a few shallow bowls. Help him add drops of coloring to each bowl so he can make crystals of different colors. Count the drops of color together, and talk about what happens when he adds more color. After the water has evaporated and he’s looking at the crystals, talk about the colors and the shapes the crystals make.
Older kids: Scientists observe and document the results of their experiments. Give your child a clipboard so she can make notes. Encourage her to record when she puts the bowl in a warm place, how long it took for the water to evaporate, and what she thinks the crystals will look like. Then have her draw what she observes under the magnifying glass. Put the bowl of crystals and her records together on display in the house so she can be proud of her scientific work.